Tap or thread-cutter.



No. 775,672. PATENTED NOV. 22, 1904.

T. DOLLARD. TA-P 0R THREAD GUTTER.

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TAP 0R THREAD CUTTER.

APPLIOA'I'ION FILED MAB. 4, 1904.

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UNITED STATES Patented November 22, 1904.

PATENT OFFICE.

THOMAS DOLLARD, OF BROOKLYN, NEW YORK, ASSIGNOR OF ONE-HALF TO HUGOWINTNER AND WILLIAM F. STRULLER, OF BROOKLYN, NEW

YORK.

TAP on THREAD-CUTTER.

SPECIFICATION forming part of Letters Patent No. 775,672, dated.November 22, 1904.

Application filed March 4., 1904.

To all whmn it may concern:

Be it known that I, THOMAS DoLLARD, a citizen of the United States ofAmerica,residing at Brooklyn, Kings county, New York, have inventedcertain neW and useful Improvements in Taps or Thread-Outters,'of whichthe following is a specification, reference being had to theaccompanying drawings, forming part of the same, in which Figure 1 is aside elevation of a tap embodying my invention. Fig. 2 is a centralvertical longitudinal section thereof. Fig. 3 is a front elevation. Fig.4 is a vertical cross-sectional view on line 4 4 of Fig. 2. Fig. 5 is asimilar sectional view on line 5 5. Fig. 6 is a detail view, partly insection, of the tripping mechanism. Fig. 7 is a perspective of thecrank-pin, the crank, and pinion; and Fig. 8 is a perspective view ofone of the cutters.

My invention relates to taps for threading pipes, nuts, and articlesrequiring an interior thread; and it consists in the combination ofdevices whereby the cutting-blades are projected to a cutting position,are held there, are retracted to permit ready withdrawal of the tool,the retracting devices are automatically brought into action, andvarious other operations are accomplished.

In the form shown the stock, for convenien eof manufacture, is made intwo parts A t e stock proper, and A the head. The part A may be anyordinary form of stock for mounting in a lathe or other operatingdevice. The head A is provided with longitudinal slots .9 in its outerface, the number (here four) corresponding to the number of bladesdesired to be used. In these slots I seat cutting-blades B, the innerside faces of which are provided with racks r and the outer faces ofwhich are provided with cutting-teeth t. Adjacent to slots 8 theheadpiece is bored at O to accommodate shafts P, which near the outerends are each cut to form partial pinions, two teeth being usuallysufiicient, though a greater range of opera tion is accomplished withthree .or more; but I prefer to use not more than three in order to.leave as large a surface as possible for a Serial No. 196,538. (Nomodel.)

firm bearing for the shafts P upon the walls or orifices O.

On the end of stock A, I'locate a case'O for holding a part of theprojecting and retracting devices, said case O being closed by acap O,fitting closely therein and centrally bored to accommodate and securelyhold the inner end of head-piece A, all parts being preferably securelythreaded together.

Within case O, I place a wheel. or disk D, -journaled on the inner endof piece A, and near its outer circumference I provide circular orifices0, in which I journal crank-pin p. Cranks 0 are secured to or formed onthe inner ends of shafts P and. are connected to crank-pins 10 bypassing through openings in the forward ends of said crank-pins.

A .-cap piece 0, secured, preferably by screws, to the head A, holds thecuttingblades B longitudinally in place.

The rear face of case O O has a section removed, (see dotted line, Fig.4.) giving access to the rear face of disk D. and to this disk alever-handle H is securely attached, having a stroke of course equal tothe width of the opening in case O O less the width of the handle.

On the outer face of cap O, I secure a block E, extending over thehead-piece, and in it are ways to to accommodate aslide S, centrallyslotted at s and holding therein a screw 6, which holds a slottedcontact-piece E, carrying a bearing-roller 2 at its outer end.

A leaf-spring L, interposed between the end of slide S and the face ofcap O, tends to keep the slide and contact-piece extended at its innerend slide S, carries also a catch-piece F, secured there'to by a screw6, extended through slot .9 the piece F being consequently capable ofadjustment on said slide.

Piece F has an arm F extending to the rear and is there provided withthe catch proper, marked J, which extends inwardly and is provided witha beveled edge j, adapted to engage a projection h on thelever H.Astrong spring G is linked to lever H and an arm K, extending from thecase O, and threaded on the head-piece A are two jam-nuts N and N.

The operation of the parts is manifest.

v by tightening-screw a.

Swinging lever H to the left turns disk D correspondingly, and thatcauses cranks 0 to be turned through an arc of a circle, which rotatesshaft P and by the action of their partial pinions and the racks onblades B projects those blades. When they have reached such points thata circle contacting their outer faces is of the required diameter of thethread to be cut, the hook or catch is brought to position to cause thelip at f of catch J to engage the projection 72 and then secured byturning down tightly the screw 0, and the blades will thus be locked inposition. Now the contact-piece on slide S is extended until itsbearing-roller is the same distance from the outer edge of thecutting-teeth t as the desired length of thread to be cut and secured inthat position The tool is now ready for use and by reason of theextended circumferential bearing of shafts P in the headpiece A theblades are very firmly held and not liable to yield from the stress ofcutting. When the required length of cut has been reached, the roller rof the contact-piece IE will be brought against the pipe or otherarticle being cut and will thereby be forced backward, carrying the lipof catch J out of engagement with projection 7L and surrendering lever Lto the stress of spring G, which will immediately carry that to theright and disk D and pins 19 as well,,thereby' rotating shafts P and (bya positive movement) retracting the cutting-blades B, so that the toolmay be readily drawn out of the threaded pipe or nut without the tediousoperation of revolving it until it runs out, (as with the ordinary tap.)To tap another pipe with a similar thread, it is only necessary to swingthe lever to the left again. The action will be as before. It is alreadyset, and the engagement of catch J and projection b will be automatic.

'If a larger pipe or nut or a smaller one is to be tapped, it is onlynecessary (within certain limits) to reset the catch-piece F tocorrespond.

If the blades are dull or one with a different thread is desired, it isbut the work of a moment to remove the cap-piece 0, draw out blades B,and sharpen and return them or substitute others.

Provision for their rigid longitudinal holding is provided in thejam-nuts N N, which when bladesB are in place may be turned, first oneand then the other, until it and they are locked firmly in place.

The action of this is tool always positive,

its adjustment simple and easy, and at whatever degree of projection theblades are set their bearings are always ample and not liable to injury.Again, by operating the shafts by cranks connected to pins .near theperiphery of disk D, I gain much power for throwing them easily andholding them firmly, the

socket-and-pin connection furnishing all the movement required to permitthe ready turning of the locked parts on different centers, whileotherwise preserving the rigidity of the connection and avoiding lostmotion.

What I claim as my invention, and desire to 2. In a thread-cutter, thecombination of a 4 stock, a head-piece, cutting-blades with racks, twoor more shafts with long bearings in the head-piece and pinion-teeth onone side engaging respectively the respective racks of thecutting-blades, cranks secured to the respective shafts, a movable diskor ring, pins connecting the said cranks to the saiddisk, a casepartially inclosing the disk, cranks, head-piece and shafts, and a leversecured to said disk and extending through said case,together with meansfor holding said lever in a given position, a'll substantially as setforth.

3. In a thread-cutter, the combination of a stock, a head-piece,cutting-blades with racks, shafts with long bearings and havingpinionteeth on one side, and a full bearing upon the other side thereof,the pinions engaging respectively the respective cutter-blades, and.

means for operating said shafts and blades, including a lever andconnections, all substantially as set forth.

In testimony whereof I have signed my name to this specification,in thepresence of two subscribing witnesses, this 27th day of February, 1904.

THOS. DOLLARD.

Witnesses:

H. M. VERMILYA, A. G. N. VERMILYA.

